I would stick with your original intensity. In my experience, lowering intensity gets lower rejects, but at the end of the day, you are submitting less shares (after a really long period). Short term it looks better to get your rejects down, and if we lived in a perfect world, you could rely on it working out. However, mining is imperfect and fluctuates constantly, especially in multi coin pools. So sticking with your original WU of 1770 will pay off in the long run because you are essentially raising your "luck" factor. Multicoin pools have higher rejects than regular pools. It's just the way it is when your dealing with lots of coin switches, different block rates and difficulties. I think way too many people over think thier rejects and forget that rejects fluctuate constantly. You may have 9% one hour, but you may only have 1% the next hour. In the end, it's best to throw all your hashing power in, set it and forget it. You have to think long term. Short term variance is very high on multi pools. It's all about your payout over time.